Getting To Know hot rolled coil + The exceptional price of buying hot rolled coil
As you know, sheets are generally produced in two ways: cold rolling and hot rolling. Investing in companies that are working on steel products is one of the best choices all around the world.
hot rolled coil
The formation of steel is called rolling. Rolling is done by passing the steel through many rolls at a certain temperature. Most of the various sections such as beams, angles, guards, and plates are produced by hot and cold rolling.
Differentiating between hot and cold dishes is often a concern for consumers.
Plates produced by hot rolling are called hot-rolled plates. This process is carried out at a high temperature and high temperature, because at high temperature, the plasticity and formation of steel are easily achieved, and its size and length change.
Typically, the steel production temperature for this method is 1200°C or 926°C.
This temperature is higher than the recrystallization temperature of the steel. After the steel is heated, it passes between two rollers moving in opposite directions.
We had to pay attention to all parts of the heated sheets. After cooling the plate, other processes such as grinding or pickling are required.
Advantages of hot plate: The advantages of hot plate include high flexibility and weldability, a simple production process, can produce larger parts, such as steel profiles for construction, railway construction, beam construction, lower product prices, etc.
Disadvantages of hot rolling: The quality of hot rolled plates is poor, and the surface is uneven, which can be removed to some extent by pickling and other operations, but the quality of hot plates is lower than cold plates.
Applications of heating plates: Heating plates are used in building and shed construction, automobile, and transport industry, agricultural industry, tank construction, etc.
In hot rolling, the metal passes between two rollers, the distance between the two rollers is slightly less than the thickness of the incoming metal, the two rollers rotate in opposite directions.
the rollers and the metal push the metal forward, the length increases, and the length decreases its thickness.
The amount of thickness reduction during rolling depends on the amount of friction between the roll and the metal surface, so the roll slides on it instead of moving the material to large deformations.
In hot rolling, temperature control is important, and for this reason it is better to raise the temperature of the metal uniformly to a certain amount.
The rolling process requires the parts to be kept at a certain temperature for a long time. If the temperature of the parts is not uniform, the resulting deformation is also not uniform.
For example, if the parts are heated insufficiently and unevenly, then the hot outer surface, they are rolled to the cooler and stronger inner surface, and if the metal is cooled after heating the workpiece or between two rolls, the cooled surface resists deformation.
As a result, parts may experience cracks or surface breaks as the hotter and weaker internal shape changes. In factories with high production volumes, molded products are often used.
After continuous casting, controlled cooling allows the product to be placed in the hot rolling mill without reheating and movement.
hot rolled coil steel
For heating in small production or secondary operations, the temperature of the raw material (ingot, billet or plate) is usually room temperature. To heat these parts to the correct temperature, they can be heated in an oil or gas oven.
Tempering is usually around 1200°C (2200°F) for plain carbon and low alloy steels, and induction furnace heating can be used for small diameter bars. Hot rolling normally stops at approx. 50 to 100 °C (100 to 200 °F) above the recrystallization temperature.
Ending the rolling process at this final temperature prevents strain hardening of the material and produces fine, uniform grains. Before further deformation, the part must be reheated to a suitable condition for rolling.
Components of a hot rolling mill
The main components required for the rolling mill are as follows:
Preheating furnace: This furnace is responsible for heating the workpiece to the temperature required for rolling.
For furnaces, a system should be designed so that the embers move through the furnace and enter from the beginning of the furnace, and when they reach the end of the furnace, the embers have reached the desired temperature.
Ejector: The job of this device is to remove the ingot that has been heated to the temperature required for rolling.
Peeler: The task of this device is to remove the skin created by molding and reapplying the cream in various ways.
Roll Stand: This equipment is used to roll workpieces or reduce the thickness of parts, which is done with the help of horizontal rollers.
edger stand: This device is used to create relatively accurate dimensions in terms of width and uniformity on the sides of the sheet, it performs this task with vertical rollers.
Thickness gauge equipment: This equipment is responsible for measuring the thickness of the produced sheet.
Stretcher: This equipment is used to stretch the sheet after production, it passes several small rollers to perform this task.
Cooling line: This line is responsible for cooling the produced plates and is designed according to local conditions.
Scissors: Its job is to cut the head and end of the paper and adjust the size of the paper.
Packaging machine: This machine is tasked with weighing sheets and automatically packing the produced sheets.
hot rolled coil companies around the world
Hot rolling or hot rolled coil is the process of rolling a bar into a thinner plate in companies all around the world. In the 17th century, two cast iron rollers were used for this. Over time, the rollers get bigger, powered by horsepower or water blades.
At the same time, they groove the rollers that make the hot work product. Gradually use the smaller roller to move the larger roller to reduce the force required to move the roller.
Sometime later, with the invention of the steam engine, they were used for this process. As industry developed, this method was used to replace methods such as forging and baking to produce metals.
In hot-rolled plates, strips, corners, steel plates and rebars, the metal is rotated between two rolls at a distance less than the input metal thickness in opposite directions. The degree of thinning during hot rolling depends on the amount of friction between the roll and the metal surface.
In metalworking, rolling is the process of passing metal through one or more pairs of rollers and reducing its thickness. This process is carried out to make the thickness uniform or to achieve the desired mechanical properties.
Rolling can be carried out at different temperatures and is used to produce different products such as sheets, profiles, rods etc.
hot rolling temperature
In the hot rolling method, temperature control is important, so it is best to raise the metal temperature to a certain amount first.
The rolling process requires that the part be kept warm for a long time at a specific temperature. If the temperature of the part is not uniform, the deformation will not be uniform.
hot rolled coil price
For example, if the part is not heated sufficiently and evenly, the hotter outer surface will roll faster than the inner surface. At the same time, if the piece of metal is cooled after heating, the cooled surface resists deformation.
So if the mold inside is hot and weak, the part may crack or the surface may crack. Factories that produce hot-rolled metal often use cast products.
After the continuous casting operation, controlled cooling allows the product to enter the hot rolling mill without heating and processing.
For heating small ingots or secondary operations, the feed temperature is usually room temperature. To preheat these parts to the correct temperature, you can place them in an oil or gas oven.
In ordinary carbon steel and low-alloy steel, the temperature is usually 1200 degrees Celsius. For small diameter rods, they use an induction furnace for heating.
Hot rolling is usually stopped at temperatures from 50 to 100 degrees Celsius above the recrystallization temperature.
Ending the rolling operation at this final temperature prevents the material from hardening and produces fine, uniform grains. Before further deformation, the part must be reheated to achieve correct rolling conditions.
hot rolling applications
The use of roller presses is preferred over many forming methods. One of their uses is the production of sheets of different thicknesses. Sheets produced in this way have excellent mechanical properties.
Sheets can be a little more expensive, but worth the money. Today, in the steel market, heat acts on the manufacture of the following sections:
- sheet
- corner
- beam
- study
- use
- rebar
Factory Hot Rolling Line Components
The main components required for a hot rolling line are:
- Preheat the oven
The task of the furnace is to heat the workpiece to the temperature required for rolling.
For furnaces, a system should be established to move the ingots through the furnace, entering from the beginning of the furnace and reaching the desired temperature when the flame reaches the end.
- Drafts
This unit is responsible for removing the ingots that have reached the temperature required for rolling.
- Peels
This device is responsible for removing the skin created during the casting process.
- Hot rolling stand
This section includes horizontal rolls to reduce the thickness of the part.
- edger stand
This tool is used to create relatively accurate dimensions in the width and uniformity of the edge of the sheet.
- Thickness gauge
This equipment is responsible for measuring the thickness of the produced sheet.
- Swing
Swing is used to rotate the sheet after production. This machine works with small rolls.
- Cooling line
The line is used for cooling production plates and is designed according to local conditions.
- Scissors
It is responsible for cutting the heads and ends of the sheet and shaping the sheet.
- Packing machine
The machine automatically takes care of sheet weight and produces sheet packaging.
hot rolling annealing
During some hot working processes, the metal undergoes many physical changes, so in this case heat treatment will be necessary.
This heat treatment gives the metal a better metallurgical condition and improves its mechanical properties. One of the most important types of heat treatment is annealing or annealing.
In this process, by keeping the cooled steel at a temperature above the recrystallization temperature, the desired metallic composition and mechanical properties are produced in the steel for a certain period of time.
hot rolled coil vs cold rolled coil
An important goal of this process is to facilitate and restore the original properties of the material. This process is carried out continuously in the furnace and the types of annealing of the formed parts are:
- Fully annealed
The metal is heated and cooled over a period of time and the final composition of the product will be coarse-grained. In this case, the metal has good elasticity.
- Isothermal annealing
With this method, the steel cools faster than before and a metallurgical state is created under isothermal conditions. In the annealed type, a fine-grained pearlite structure is formed.
- Spherical annealing
In this section, by annealing and normalizing the steel, they spheroid the carbides in the steel structure.
- Hot work
This is another thermal process where plastic deformation of the material occurs at temperatures above the recrystallization temperature of the metal.
Advantages of hot rolling
In hot rolling, the silane tension decreases due to the preheating of the part as the temperature increases, which ultimately improves the formability of the metal. For this reason, this method is often used for rolling and thinning high-thickness ingots.
Disadvantages of hot rolling
- The output product does not have very good dimensional accuracy.
- It increases the friction coefficient after the rolling process.
- Metals oxidize when exposed to high temperatures.
- In some products, such as steel beams, a rough texture occurs.
- Sometimes it causes many changes in material properties. For steel, for example, blue embrittlement occurs at temperatures between 250 and 350 degrees Celsius.
- Due to the high operating temperature and the oxidation of the metal surface, hot rolled products tend to look ugly and become black in color.
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